1. adj. Used of hardware or
software designs, implies ‘elegance in the small’, that is, a
design or implementation that may not hold any surprises but does things in
a way that is reasonably intuitive and relatively easy to comprehend from
the outside. The antonym is ‘grungy’ or
crufty.

2. v. To remove unneeded or
undesired files in a effort to reduce clutter: “I'm cleaning up my
account.” “I cleaned up the garbage and now have 100 Meg free
on that partition.”